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Ductless Air Conditioners: How Do They Work?

Conventional HVAC systems depend on ducts to deliver conditioned or warm air throughout indoor spaces. However, not all homes have existing ductwork, especially older structures. If this is the case for you, consider a ductless air conditioner. Also called mini-split, this equipment has been increasing in popularity due to its flexibility, convenience and energy efficiency. 

One of the area’s leading heating and air conditioner maintenance companies explains how ductless air conditioners work. 

What Is a Ductless Air Conditioning System?

A ductless air conditioner does not have ducts like a central AC. It takes warm air from the room and returns it as cool air. This equipment is a great alternative to standard ACs due to its ease of installation, sleekness and quiet operation. 

You can use ductless ACs to keep your entire house comfortable. Several indoor units can be connected to a single outdoor compressor that gets all the warm air from your living space. After installing the main unit, you can choose from several indoor unit options. HVAC installation companies can install ductless ACs in ceilings, floors and walls, depending on your needs and the structure of your home.

What Are Its Components?


You will find a ductless AC condenser outdoors. It contains a mechanical compressor, fan, expansion valve and evaporator coil. This component absorbs warm indoor air from your home and dispels it outside. 

Evaporator or Blower Unit

HVAC installation companies may refer to the indoor unit of a ductless AC as an evaporator or blower unit. It’s usually thin and around 3 inches long. This component draws warm, humid air from the room and delivers it back as cold air. It cools indoor spaces while taking heat and moisture outdoors. 


The conduit joins the indoor and outdoor units together. It is typically a thin, long cable that covers the power cable, condensate drain and refrigerant tubing. This part of a ductless AC delivers electricity to indoor and outdoor units. It is also where heat and moisture from inside the house travel to the condenser. 

How Does a Ductless Air Conditioner Work?

Refrigerant Cycle

The refrigerant is a cooling agent that is either in a gas or liquid form. It works with other system components, such as evaporators and compressors, to bring heat outdoors and deliver conditioned air indoors. 

When refrigerant takes the heat from a room, it transforms from a low-pressure gas to a high-pressure liquid. AC system components bring the refrigerant outdoors, where a fan pushes hot air over the coils and expels it. The refrigerant cools and becomes a low-pressure gas again. Another indoor fan blows air over the cool coils to circulate conditioned air within the house. This cycle repeats as long as the ductless AC is running. 


The compressor is responsible for converting the refrigerant from a cool, low-pressure liquid into a high-pressure gas and vice versa. Other components of the AC use temperature change to generate conditioned air, making your indoor spaces comfortable. 


High-pressure, hot refrigerant from the compressor goes to the condenser or outdoor unit, where it flows through a set of coils and lowers in temperature. The refrigerant remains in a pressurized liquid when it arrives at the end of the coils but without heat. It then goes to the condenser through a small valve and turns back into a gaseous state.  

Expansion Valve

The expansion valve controls the flow of refrigerant in an air conditioning system. It reduces the pressure in your AC to convert liquid refrigerant in the evaporator coil to gas.  

Evaporator Coils

Evaporator coils typically come in metals that conduct heat easily, such as copper, aluminum and steel. In this part of air conditioners, the refrigerant absorbs heat. It also helps regulate how much air passes through the system for even temperature distribution. 

Why It Makes a Good Investment

Ease of Installation

There is not sufficient room for new or additional ducts in many older houses or buildings. A ductless air conditioning system is ideal for homes without pre-existing ductwork. Moreover, heating and air conditioner maintenance companies can easily install this equipment since it does not require making large openings on ceilings, walls and floors. 

Meet Different Heating and Cooling Needs

With a ductless AC, you can meet the heating and cooling demands of everyone in the family. This equipment features built-in zoning, allowing you to set rooms at different temperatures. Each indoor unit has a remote control, allowing you to cool your indoor spaces at varying temperatures.

Enjoy Savings on Energy Costs

According to ENERGY STAR®, leaky ducts are responsible for around 20 to 30% of energy loss in your home. Holes, gaps and cracks in your ductwork will make your HVAC system work harder to reach your desired temperature. They can cause your equipment to short cycle and consume more energy, increasing utility bills. When you invest in a ductless AC, you do not have to worry about this issue. You can also save on HVAC repair costs. 

Ideal Option for Home Additions

Before installing an HVAC system, experts will measure your space to determine which type of unit is appropriate for the size of your home. If you are adding a new room to your house, consider a ductless AC. Your current heating and cooling equipment might not be able to handle the extra load from your addition. When this happens, it will struggle to keep your indoor spaces comfortable. 

Keep Your Ductless AC in Top Shape

Ductless ACs require regular tune-ups like other heating    and cooling equipment. With proper maintenance from experienced professionals, your AC will last longer and stay efficient. Routine care can also help reduce the likelihood of breakdowns and early system failure.  

You can count on Cafco Services for superior HVAC repair, installation and maintenance services. Our experienced technicians are here to ensure your equipment runs smoothly, no matter the season. We also provide effective indoor air quality solutions. Call us at (513) 242-3400 or complete our online form to schedule an appointment.